Lisha Xu

Critical behavior and long-range ferromagnetic order in perovskite manganite Nd0.55Sr0.45MnO3

The critical behavior of perovskite manganite Nd0.55Sr0.45MnO3 has been investigated based on the static magnetization measurement around the paramagnetic-ferromagnetic transition temperature 273 K. A large critical exponent and a small one have been obtained by calculating the magnetic-field dependence of the magnetic-entropy change and the Widom scaling relation. These critical exponents not only obey the scaling hypothesis, but also corroborate the results obtained from the Kouvel-Fisher method. In comparison with the values given by standard models, these obtained exponents are very close to those expected from the mean-field model ( and ) and its magnetic-coupling type belongs to nearly long-range interaction. We suggest that the A-site spin disorder and localized magnetic phase competition are the main reasons for the actual critical exponents to show a slight deviation from the theoretical model.

Magnetic entropy change and accurate determination of Curie temperature in single-crystalline helimagnet FeGe

Cubic helimagnet FeGe has emerged as a class of skyrmion materials near room temperature that may impact future information technology. Experimentally identifying the detailed properties of skyrmion materials enables their practical application acceleratedly. Here we study the magnetic entropy change (MEC) of single-crystalline FeGe in its precursor region and clarify its close relation to the critical exponents of a second-order phase transition in this area. The maximum MEC is found to be 2.86 J/kg K for a 7.0 T magnetic-field change smaller than that of common magnetocaloric materials indicating the multiplicity and complexity of the magnetic structure phases in the precursor region. This result also implies that the competition among the multimagnetic phases can partly counteract the magnetic-field–driven force and establishes a stable balance. Based on the obtained MEC and the critical exponents, the exact Curie temperature of single-crystalline FeGe under zero magnetic field is confirmed to be 279.1 K, higher than the previously reported 278.2 K. This finding paves the way for reconstruction of the FeGe phase diagram in the precursor region.

Magnetic field-driven 3D-Heisenberg-like phase transition in single crystalline helimagnet FeGe

Significant microscopic information about fundamental magnetic interactions of magnetic materials is probed via the critical behavior of paramagnetic-ferromagnetic phase transition. In this work, we demonstrate that the critical behavior of cubic single crystalline FeGe belongs to the isotropic 3D-Heisenberg universality class by measuring the field dependence of magnetic entropy change. The above transition is one of the magnetic field-driven phase transitions but has a feature of the crossover from first- to second-order phase transition. A phenomenological model based on the evolution of magnetic skyrmions was proposed to qualitatively understand the phase transition.

Effect of A-site average radius and cation disorder on magnetism and electronic properties in manganite \(\hbox {La}_{0.6}\hbox {A}_{0.1}\hbox {Sr}_{0.3}\hbox {MnO}_{3}\) (A = Sm, Dy, Er)

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Magnetocaloric effect and spontaneous magnetization in perovskite manganite Nd0.55Sr0.45MnO3

\hbox {La}_{0.6}\hbox {A}_{0.1}\hbox {Sr}_{0.3}\hbox {MnO}_{3}

Impact of disorder effect on the percolative conductivity in Nd0.5Ca0.5−xSrxMnO3 (0.10 ≤ x ≤ 0.25)

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Structural, magnetic, and magnetocaloric properties of bilayer manganite La1.38Sr1.62Mn2O7

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